1. Field of the Invention
The present invention generally concerns drywall finishing tools.
The present invention particularly concerns a drywall finishing tool directed to the manipulation of drywall compound in selected wall joints that are formed from and by drywall panels abutting at a particular range of angles.
2. Description of the Prior Art
2.1 General Drywall Finishing
The tool of the present invention can be sufficiently understood without having much understanding of, nor appreciation for, the drywall finishing process. However, a good hand tool is not merely operative in a process, but facilitates, or even dictates--hopefully in a new and improved manner--the performance of the process. Accordingly, some understanding of the drywall finishing process is not adverse to appreciation of the tool of the present invention.
The finishing of drywall is sometimes called taping, or even spackling. As well as shaping tools like that of the present invention, a compound pan and 5", 8", and 10" drywall knives are generally used. Some drywall finishers prefer a 6-in. tool for applying the first coat of compound, followed with a 10-in. tool for the second coat and a 12-in. blade for the final skim coat. Generally speaking, wider knives are harder to control. All tool blades are desirably flexible, and the tool of the present invention will also be seen to be flexible.
Selection of compound is important. Compound is available in two types. One is called a setting compound that hardens by a chemical reaction. The other is a drying compound that cures by evaporation. The latter is available in powder or a ready-mix version, but for most people the ready-mix version is much more convenient. A typical compound suitable for use with existing tools and with the tool of the present invention is the relatively new ready-mix drying compound called Lightweight Plus 3 available from United States Gypsum (USG). It reportedly shrinks less, weighs less and is easier to sand than the company's standard drying compound, without sacrificing any strength.
Joint tape may be either paper tape or a self-sticking fiberglass mesh tape. The great advantage of the fiberglass tape is that it eliminates the need for the first coat of compound--and that's a major saving in labor. But tape manufacturers say the fiberglass product should be used only with setting compounds, not drying ones. In the opinion of many professionals the difficulties of working with a setting compound outweigh the advantage of using the fiberglass tape.
There are various approaches to the finishing process. However, a few rules of thumb are always approprialean as possible.
This means wiping off the excess compound on the edge of the pan after each pass with the tool. Second, dried compound is never mixed into fresh compound. Even the smallest piece of dried debris will leave a messy gouge in the finished surface. If dried compound finds its way into a pan or pail, it must be removed immediately. Finally, the surface of the compound will be only as smooth as the stroke you use to apply it. (The tool of the present invention will be seen to excel in supporting smooth and even stroking of drywall compound.) In the beginning, an inexperienced finisher should make a concerted effort to lengthen his/her strokes and keep the tool aligned with the direction of the joint. Until a finisher accrues experience and gets the knack, compound may squeeze off the tool and fall to the floor. But by loading the tool with less compound, the finisher can usually minimize the mess.
Joint sequence usually begins with the butt joints--those on the ends of the boards--followed by tapered joints--those along the edges--followed by inside corners and then outside corners. (The tool of the present invention will be seen to be applicable to both inside and outside corners.) With normal straight-edge tools inside corners normally have to be done in two steps because it is only possible to work on one side of the joint at a time. If any attempt is made to finish both sides at once, a conventional straight-edge tool will foul the first side while work is attempted on the second side. (The tool of the present invention, like some few others in the prior art, will be seen to advantageously permit finishing both sides of an inside corner at one time.)
2.2 Finishing of Butt and Tapered Joints
Although the finishing of butt and tapered joints will be seen to be substantially irrelevant to the preferred use of the tool of the present invention, the conventional manner of finishing these joints will be discussed in a few paragraphs within this BACKGROUND OF THE INVENTION section for ease of later comparison to the preferred techniques, and steps, for using the tool of the present invention. Drywall finishing work begins by mixing of joint compound, sometimes called mud. Although mixing isn't absolutely necessary with ready-mix compounds, to do so smooths out the compound and makes it easier to apply. Starting at a butt joint, the finisher loads up a 5-in. tool, making sure that its corners are clean, and applies the compound starting at one end of the joint. Application proceeds as smoothly as possible, the tool being reloaded when depleted of compound. The cleaning of the tool on the side of the pan and the smoothing of the entire joint preferably transpires in one stroke.
The tool is not pressed so hard that all of the compound is removed. If the surface is scraped clean in an area, compound must be re-applied because the paper tape won't stick to the paper covering on the drywall without compound underneath. Once the compound is smooth, a piece of joint tape is cut to length and embed in the compound by use of the fingers. The middle of the paper is aligned directly over the middle of the butt joint.
The tape is smoothed into the compound with a 5-in. tool, any excess that squeezes out being wiped off. The goal is to get enough compound on the wall to hold the tape, but not so much as to leave a noticeable bump. After practice a finisher is able to get a relatively smooth surface with the tape straight and flat.
Once the tape is in place, the entire joint is covered with more compound, this time using an 8-in. tool. The same techniques are employed as described for the 5-in. tool.
One of the most difficult joints is a ceiling butt joint. In the first place, the finisher is working over his or her head, which is always awkward. And in the second, a butt joint has no tapered edges that tend to hold compound better. To start such a joint, the tool is loaded as before and pressed against the ceiling. The tool is then slowly moved across the joint in a smooth stroke while being progressively flattened during the course of movement. This motion helps reduce falling compound while at the same time yielding a smoother surface. This movement is difficult for beginners, but, with practice, mess can be held to a minimum.
Tapered joints are easier to finish because of the depression built into the long edges of all drywall panels. They are nonetheless approached just like the butt joints. First, the joint is filled the joint with compound using a 5-in. tool. Then, the tape is embedded by use of the fingers, and smoothed into place with the 5-in. tool. Finally, the first coat is finished by applying compound with an 8-in. tool. When doing flatwork, as the butt and tapered joints are sometimes called, it makes sense to cover all screw and/or nailheads, too. Joint compound is simply over each of them, with any excess scraped off.
2.3 Corner Joints
Corner joints, both inside and outside, will be seen to be most similar to certain other particular joints that are the province of the tool of the present invention. As mentioned ear except the first--of the finishing process has to be done in two steps, to allow drying time in between. Although this seems inconvenient, sensible planning permits organizing work in a way that incorporates the needed drying time.
To start an inside joint, a 5-in. tool is first loaded on one corner only. The compound is then applied to one wall only with a smooth, steady stroke. Working in this fashion limits the amount of compound that squeezes out. The other corner of the tool is then loaded and used to coat the other side of the joint. Fouling of the first side while coating the second is inevitable, but should be avoided as much as possible.
A piece of tape is next cut to length and folded down the middle. The tape is carefully pushed into the joint by use of the fingers. The fold in the paper must lines up with the corner of the joint. The tape is embedded on one side of the joint at a time using a 5-in. tool. The finisher does not bear down hard, but keeps steady and even pressure on the tool, doing his or her best to keep the surface smooth. Once the excess compound has been removed from both sides, a top coat is applied to one side of the joint using an 8-in. tool.
The inside corners along the ceiling are finished in the same way. When those are complete, move on to any outside corners. The first step in finishing these is to attach metal corner bead to the joint with drywall screws or nails. Then, using an 8-in. tool, the area over the corner bead is filled with compound. Work proceeds on one side first and then on the other.
Coat both sides of all inside corners completes the first coat of compound. Once everything is dry, any ridges or chunks of dried compound are scraped off by use of the 5-in. tool. If the job of applying the compound was done reasonably, sanding isn't necessary.
Any depression is easy to fill on the next coat, but a ridge will prevent the tool from laying flat and will ruin any hopes of a smooth second tool is used to apply a second coat of compound, following the same joint sequence as was followed for the first coat. The whole process is repeated for a third coat. When this coat is dry, the surface is sanded with 180- or 220-grit paper.
When the mess is vacuumed up, and a coat of primer applied to the walls, the walls will then be ready for paint or wallpaper.
2.4 Automated Taping Tools
Successful completion of any drywall job--large or small--takes skill, time and effort. Certain tools available from Ames Taping Tool Systems Company, Inc. are eminently compatible, and usable, with the tool of the present invention. Ames tools are standard in the U.S. drywall installation and finishing industry, Ames having provided drywall contractors, tapers and finishers with automated equipment since 1939. Ames equipments currently produce the highest quality, most cost effective method of taping and finishing drywall.
In particular, the Ames Bazooka.TM. brand automatic taper simultaneously applies tape and joint compound to all wallboard joints--horizontal and vertical joints, ceiling joints, interior/exterior corners and angles. (Bazooka.TM. is a registered trademark of Ames Taping Tool Systems Company, Inc.) The Bazooka taper automatically dispenses the precise amount of tape and compound for fast, efficient operation. It is used in conjunction with other tools such a corner roller, a flat finisher,. a corner applicator, a corner finisher, a nail spotter, a loading pump, a gooseneck adapter, and finisher handles.
The Ames Bazooka.TM. brand automatic taper may suitably be used for initial application of tape and joint compound to the selfsame particular drywall joints that will later be seen to suitably be finished by the drywall finishing tool of the present invention.
2.5 Particular Previous Drywall Finishing Tools
U.S. Pat. No. 4,097,951 to Hurtt for a SPREADER HAVING INTEGRALLY MOLDED DEFORMABLE HANDLE AND BENDABLE BLADE concerns a toll alleged to be especially effective for use with fast hardening metal fillers comprising resin and a catalyst. The spreader, which may be integrally molded in a continuous combination of injection and blow molding, comprises (i) an elongated handle which is hollow and deformable and (ii) a blade which is solid, whereby sculpturing and contouring may be achieved more readily through hand manipulation and the spreader may be more easily cleaned.
The precturable by molding, and deformable in use.
U.S. Pat. No. 4,654,919 for a SPREADER TOOL FOR APPLYING PLASTER AND CEMENT TO WALLBOARD, AND THE LIKE to Liberman concerns a tool for spreading plaster, or the like, on wallboard surfaces. In a first embodiment the tool includes a contoured surface having two end tip portions and a mid-portion contained in a plane spaced from the end tip portions. The tool includes a backing layer which gives structural integrity to the tool, and a flexible application-surface layer which projects beyond the outer edge of the backing layer. In use, the plaster is applied to the wallboard surface, and the projecting outer edge of the flexible layer is forced against the wall and pulled along to obtain a flat surface to spread the plaster out along the wallboard surface in an even and smooth manner to cover up cracks and tape. In a second embodiment, approximately half of the tool has a contoured surface, with the other half being planar. In this embodiment, the tool is used to distribute the plaster along the general wallboard surface area. This is accomplished by applying pressure to the planar portion to cause the plaster to extend outwardly between the curved portion of the tool and the adjacent wallboard surface. The tool is then used to smooth out that portion of the plaster positioned between the curved portion and the wallboard portion.
The present invention will be found to involve a tool that also has and presents contours. However, the contours of the tool of the present invention will later be observed, in accordance with the tool's function performed on a workpiece wall of different contour than is addressed by the Liberman tool, to be different than the Liberman tool.
U.S. Pat. No. 4,784,598 to Kranz, et. al. for a DRYWALL TOOL concerns a tool for applying drywall compound to a drywall joint is disclosed. The tool includes an application member of resilient flexible material. The member has a generally flat application surface and an arcuate application edge. The application edge and the thickness of the application member are selected for a central portion of the edge to be urged against a joint defined by contiguous flat drywall sheets. The application surface on opposite sides of the central portion flex to define a smooth continuous surface from the central portion to points on the drywall sheets spaced from the joint. The tool urges drywall compound within the joint to assume a smooth surface filling the joint and fanned away from the joint into smooth continuity with the drywall sheets.
The Kranz, et al. tool is perhaps the most visually similarly appearing to the tool of the present invention, which will also be found to be of resilient flexible material. However, the contours of the tool of the present invention will later be observed, in accordance with the tool's function performed on a workpiece wall of different contour than is addressed by the Kranz, et al. tool, to be different than the Kranz, et al. tool
U.S. Pat. No. 4,946,360 to Brown for a FINISHING TOOL concerns a finishing tool providing a smooth finish to taped coved joints or to corner joints having an angle greater than ninety degree defined by converging wall board surfaces is presented. The finishing tool includes a working plate and a supporting plate, each being provided with a substantially straight edge disposed transversely to the longitudinal axes of the tool. Each of the working and supporting plates is formed of resilient material to provide longitudinal and latitudinal flexural movement so as to allow the entire length of the straight edge of the working plate to engage seam sealing material applied to the corner joint and the adjacent wall board surfaces to provided the corner joint.
The Brown tool, although distinctly different than the tool of the present invention, will later be seen to deal with corner joints that, in having a greater than ninety degree angle, are representative of some (but not all) of the joints dealt with by the tool of the present invention.
U.S. Pat. No. 5,010,618 for a CORNER FINISHING TOOL to Croft concerns a corner finishing tool for use in drywall finishing that consists of wings spreading from a center ridge that is configured to cut through drywall compound ("mud") on a wall corner, the wings including mud dams formed on their wall engaging faces to smooth tops from the mud and to spread a mud impregnated tape in from that wall joint and to direct excess mud into a space formed by that ridge, the dams and a flange projecting rearwardly from the peripheral edges of the wings.
U.S. Pat. No. 5,240,394 for a CORNER RADIUS TOOL to James concerns a corner radius tool is provided for use in applying plaster material or the like to an inside corner joint between drywall panels to form a controlled and smoothly joined surface. The tool includes a tool head in the form of a forwardly open resilient cup carried at a forward end of a tool handle, wherein the cup is adapted to support a quantity of the plaster material as the handle is manipulated to press and spread the plaster material along the inside corner joint. The resilient cup deforms upon engagement with the drywall panels at the corner joint to spread the plaster material with a desired and smoothly radiased surface. The specific radiased geometry of the plaster material surface is variably controlled by varying the orientation of and manual pressure applied to the resilient cup.
The Croft and the James tools are primarily of interest for showing prior art handled drywall corner tools.